Nagios NRPE example setup

Ubuntu

#> apt-get install nagios-nrpe-server nagios-nrpe-plugin

CentOS and Fedora

#> yum install nrpe nagios-plugins-load nagios-plugins-users nagios-plugins-swap nagios-plugins-disk

#> chkconfig –add nrpe

FreeBSD

#> cd /usr/ports/net-mgmt/nrpe*

#> make

#> make install clean

#> In /etc/nagios/nrpe.cfg

Set the following

dont_blame_nrpe=1 (default set is 0)

Edit the local config file to only allow the nagios servers and set the check commands

This is in /etc/nagios/nrpe_local.cfg on Ubuntu boxes

allowed_hosts=127.0.0.1,66.178.152.26,172.16.3.42,69.9.130.13,10.0.1.194,69.9.129.2,69.9.144.4,172.15.25.2,10.0.201.200

command[check_users]=/usr/lib/nagios/plugins/check_users -w 5 -c 10

command[check_load]=/usr/lib/nagios/plugins/check_load -w 15,10,5 -c 30,25,20

command[check_disk]=/usr/lib/nagios/plugins/check_disk -w 20 -c 10

command[check_zombie_procs]=/usr/lib/nagios/plugins/check_procs -w 5 -c 10 -s Z

command[check_procs]=/usr/lib/nagios/plugins/check_procs -w 150 -c 200

command[check_swap]=/usr/lib/nagios/plugins/check_swap -w 20 -c 10

On CentOS it puts the hard coded commands into /etc/nagios/nrpe.cfg there is no local file

Also add this line as it is not there by default

command[check_swap]=/usr/lib64/nagios/plugins/check_swap -w 20 -c 10

This may bee needed on 64bit machines

mkdir /usr/lib/nagios

mkdir /usr/lib/nagios/plugins

ln -s /usr/lib64/nagios/plugins/check_nrpe /usr/lib/nagios/plugins/check_nrpe

If you are running a custom firewall or standard IP tables you may need to add an allow for the port (Fedora or CentOS)

Firewall (I added under the SSH section)

#NRPE

$IPTABLES -A INPUT -p tcp -s $ANY –destination-port 5666 -j ACCEPT

Standard IP Tables

-A INPUT -p tcp -s $ANY –destination-port 5666 -j ACCEPT

Restart the firewall

Restart the nrpe server

Ubuntu

/etc/init.d/nagios-nrpe-server restart

CentOS

/etc/init.d/nrpe restart

On the monitoring server you can run this to check for a response and make sure things are talking. This can also be ran on the local machine just use 127.0.0.1 as the server IP. If you get a response on the local machine but not the nagios server you likely have a firewall rule blocking you.

/usr/lib/nagios/plugins/check_nrpe -H <SERVER IP>
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